#include <iostream>
#include <string>
#include <vector>
using namespace std;

vector<string> s;

int main() {
  ios::sync_with_stdio(0), cin.tie(0), cout.tie(0);
  int n, ans = 52;
  cin >> n;
  s.resize(n);
  ans -= n;
  for (int i = 0; i < n; i++) {
    cin >> s[i];
    for (int j = 0; j < i; j++) {
      if (s[i] == s[j]) {
        ans++;
        break;
      }
    }
  }
  cout << ans << "\n";
  return 0;
}